The existing Louisiana Highway 1 (LA-1) runs along the bank of BayouLaFourche in the coastal region of Louisiana and is a primary two-lane transportationroute for foreign oil offloaded from ships in the Gulf of Mexico. The LouisianaDepartment of Transportation and Development (LADOTD) decided to upgrade thesouthern 28 km portion to a four-lane, fully access controlled, elevated bridge. Earthenembankments link the North and South Connectors to the existing roadway. Theseembankments would have fill heights of 0.6 m to slightly over 2 meters.Even with relatively low embankment heights, consolidation settlements of 46 cmto 150 cm were predicted. In order to meet the residual settlement requirement, acombination of wick drains, lightweight aggregate fill, and surcharges was used to reduceand accelerate the settlement. Vibrating wire settlement monitoring cells were used tomeasure the progress of settlement. Observations made from the settlementmeasurements indicate a strong tidal influence on the settlement behavior of theembankments. This paper presents the observed tidal impact to the settlement and theresulting difficulties associated with evaluation of the settlement data. Both Asaoka andhyperbolic curve matching methods were used to predict the final settlement values. Thetwo methods produced comparable estimated final settlement values.
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